The Center for Clinical Epidemiology and Biostatistics (CCEB) at the University of Pennsylvania proposes an innovative research training program in biostatistics for pre-doctoral training in cancer biostatistics, specifically designed to strengthen the links among biostatistics, clinical oncology, and clinical epidemiology. The training program relies on existing collaborative relationships among biostatistics and epidemiology faculty within the CCEB, faculty members within the Cancer Center of the University of Pennsylvania, and statistics faculty within the Wharton School of Business at the University of Pennsylvania. The objective of the program is to train individuals to be rigorous and independent academic investigators able to use the range of approaches in biostatistics to address research issues in cancer. This includes the application of general biostatistical methods, including the analysis of longitudinal data, such as tumor growth; the analysis of time-to-event data; meta-analysis; clinical trial design; and ethical issues in clinical research. This training also includes the application of specific biostatistical methods needed to address issues unique to cancer studies, such as informative censoring in the analysis of tumor growth data, as well as the development and application of novel biostatistical methods to such areas as the analysis of DNA microarray data. The four- to five-year training program for predoctoral students provides didactic training in fundamental skills, methodologies, and principles of biostatistics, with specific emphasis on the areas of most importance to cancer research. Specific courses are offered in general and advanced biostatistics and research methodology, leading toward a Ph.D. degree in Biostatistics. Students also will be required to obtain a strong background in substantive areas related to cancer, including cancer biology, cancer genetics, and cancer epidemiology. Courses are supplemented by attendance at and participation in research seminars and journal clubs. In addition, faculty mentors will lead students through directed experiences in collaborative research and consultation. Specifically, the training program is designed to: (1) provide in-depth knowledge of the biostatistics techniques appropriate to research in cancer; (2) provide research experience with mentors in biostatistics and cancer research; and (3) bring together faculty and students through participation in seminar series in the CCEB and the respective clinical departments. Strengths of the program are the emerging training program in biostatistics offered by the CCEB; the wide ranging experience of the biostatistics faculty in multiple areas of biostatistics methods and cancer research; the established teaching program in statistics offered by the Wharton School; the long history of successful research training programs in clinical epidemiology offered by the CCEB; and the collaborative links among biostatistics and epidemiology faculty within the CCEB, faculty members of the Cancer Center, and statistics faculty within the Wharton School. Available resources include several existing large databases available to students that can be tapped for biostatistics training, a broad array of ongoing research projects conducted within and outside the CCEB (e.g., clinical trials at all phases, case-control studies, cohort studies, and an increasing amount of research involving the use of DNA microarrays), Penn's commitment to collaborative research and training, and the broad range of experiences of faculty participating in this training program.